SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a437309aeb9d54b6b96edf06e0061b2f99edaf2176bfaed2eaa814101131e5c' 
  AND token = '5GXV+kAZKRD2MNAO1Zlmem4stDamb+JHG5rlwmg+27s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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