SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93bca6879ffb5cee5fec18c7f88978d19db1ab56807a0fb327515c38dc42dbd6' 
  AND token = 'YKgGw7ylvg+xB/pFOOpsXeo6NMRmbuRZC89NFc+4jaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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