SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '887369ed5e081f6d58afce8170514fe44baaf29f5b0b1214ab2fb6efdf7b95a7' 
  AND token = 'eMLej+7UVBJr2lcTN/xbdMcKbovgceVE29DJMobk924=' 
  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"
    }
  }
}