SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0f0948fd4b9c10766f56cccd2c2025bd3070015a63ab401f3fba47c0435895d' 
  AND token = 'W6pGrOjfQzetsQgYVQnEznPh5fKFZz904f520tO/p/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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