SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2594ef88d4e121a8143cb736bd91c654480fe53cef35fa4f4f2d554b685eb08' 
  AND token = 'ZLTaHU1JwWWF9z4T5u49On4s8zF7yzmE2X3OWN3dfuY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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