SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7172bbb23e14d522887091b43ed1578818a686825668f00ea74cc4ef63d4e98' 
  AND token = 'r1RRHCV2BCigoAs25T3n1goFMNILZloPw+3NaqP7mTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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