SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30ec6204c14f9b3175bed83c5d751a4b12f969e90019fcf239af1a2c773d254c' 
  AND token = 'YewTnLoV56iACdfO7wbhMYPkMDWg0mVSiMUJjWpYPYo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}