SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c42cdd85303cfa4f6a2d9cce8fb51decd1343977d49cd7172e1aa375a548cf06' 
  AND token = 'pvZhQKnoLVR99hdJ86FBYnZ69u2AiTwlUYjtTZXbI0Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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