SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d46cdb60178146dbddf29eadb5123b6ba80afb8921b8a7143989a79719559f5' 
  AND token = 'j01ryZN66ouzXuolWsEHbGOOm7UDbesFk5aFf2bhF7s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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