SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fda251f80396c12e19d30c87619495e4e884fb07bd84521af496073d92275b0' 
  AND token = '8yOUkVmgcQBIAHTbFoS07M+3hZfJFmDWq3bifHTTxIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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