SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3dd74ed22d4dda702ed298538519c3bfc6fcd950820808b4289886f97336822' 
  AND token = 'gXlfcwE5aI1fC2DHqV0sFX4L0G1CQt25CAsCQA2Tl30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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