SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '60c578880f2fa46bca6e656c500babf1e362b32bdc7ea0455f820a07a7133d95' 
  AND token = '4KX1VWJWIk6Yow5DQNLN2Xm+sL4RA30/rsyRNtd5ysE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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