SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b126baae25099a4ce20ea13d50d944085bf80025a8fbca0027c5bcc6601fdeb0' 
  AND token = 'pA+Pj8GZj21gBmZQ2qR4fCRqkthgJitO4brHIKgsrTk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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