SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5307b10d4adfd00c8a5e1ae1f7d8f08e73c994d5deca356295a4303269514387' 
  AND token = 'jtWLl2w5d/+Fv6PWqyaqkpfaXzPRLB2UKcHl2BtUlGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}