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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '915a01828e2a08866653c1dd8cb9a84265b68298e2fd2ea2e4c3b0a40d3ae646' 
  AND token = 'lmGJ6edyVB7+2ndsBgv9UvK8/7s2bnMUKyqB4ELegdQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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