SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e377aba45ab25460ff23ab9606031e7e35946812e235bfc3749ac059a1c047b2' 
  AND token = 'Rs2k9/TuwxY8rzH2w7KRK/tuxBQ+3RYSZLPqRrUBmkk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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