SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b83b1bb88e8c924df616d4bb9863d0fa05016151455027a7b79600bc4d79ec2b' 
  AND token = '2m/+KL4h7ALOW2JaotUlPl+NxyCKorXpPOLmRgvfIhs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}