SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9415b22e9c0791a041c535e52dfa3060718b10922fddd5576d29d5f6bc0f7e2' 
  AND token = 'fXRm/R7gtAEvOpGfURdWtzmIZ2GMvbYBJknNVqLCnKo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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