SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b975447a957af359d663ee12bfe05fcb9985eaa3d8aa0cca690fe0d0462abee' 
  AND token = 'Zr05BLAXB1i52ANf6OfRNy17JPIgQXXPkNDVPuOp31E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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