SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6074a754f5e8bb99636abde8af75f57b45b572fc71c1a87369e14802fd4732c7' 
  AND token = 'InONDdzly38cP1ZVDM4hdqREDAYBsZ5Uvm6Pe9B/Kgk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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