SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d25d15a8f426088087e06066c167c0c2737c4d4b1a9b5852104e4e45e5018d7' 
  AND token = 'xtPBhSg+AWJ0c/SziiGDVvdmoGE2LDiQfrft1NZACSI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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